Apparatus for briquetting of pulverulent or granulate-like materials,particularly anode materials for the production of aluminium



Dec. 22, 1970 BQESCH ET AL 3,548,456

APPARATUS FOR BRIQUETTING OF PULVERULENT OR GRANULATE-LTKF MATERIALS, PARTICULARLY ANODE MATERIALS FOR THE PRODUCTION OF ALUMINIUM Filed May 24, 1968 2 Sheets-Sheet 1 INVENTOR. MW 6050i [7 6'1.

Dec. 2, 197@ A BOESCH ET AL 3,548,456 APPARATUS FOR BRIQUETTING OF PULVERULENT OR GRANULATE-LIKU MATERIALS, PARTICULARLY ANODE MATERIALS FOR THE PRODUCTION OF ALUMINIUM Filed May 24. 1968 2 Sheets-Sheet 2 INVENTOR. 415% 5050/ 791.

United States Patent US. Cl. 1816.5 7 Claims ABSTRACT OF THE DISCLOSURE A method of and means for the briquetting of pulverulent or granulated materials, wetted or unwetted, particularly anode material for the production of aluminum, wherein the material is shaped into a briquette in the container of a press, by pressure exerted in a horizontal or vertical plane by a press ram or a pair of press rams, the material being evacuated immediately before being pressed into shape.

This invention relates to an apparatus for the briquetting of pulverulent of granulate-like materials, wetted with a liquid or unwetted, particularly of anode materials for the production of aluminium, wherein the mouldable material is shaped into a pressed briquette in the container of a press, by which, by means of a press ram or a pair of press rams, pressure is exerted in a horizontal or a vertical plane.

Usually the anode material for briquetting, that is,

for the production of block anodes, is poured into the container of a press and then compressed, the air contained in the container and in the anode material escaping between the container and the press ram. The extrusion time, besides the extrusion pressure is thus of decisive importance for the porosity of the pressed block anode, upon which its electrical resistance and burning-01f loss are thus dependent. If a large number of block anodes per unit of time is to be attained by the known process, that is to say, if the pressing time is small, the air does not have enough time to escape from the anode material and between the container and the press ram. This gives rise to rather large air bubbles in the pressed block anode, which results in high porosity, with the additional danger that the trapped and highly compressed air, after the loading by the press ram has been relieved, may destroy the briquet. If on the other hand a block anode of high quality, that is to say, of high density, is to be produced by the known process, the anode material must be compressed so slowly that the air enclosed in the anode material and in the container reliably escapes. The usual commercial block anodes are of a quality which is acceptable as regards pressing time and cost of manufacture, but one has to put up with hair cracks and minor crumblings, including those occasioned by inclusions of air.

Accordingly, the object of this invention is to provide an apparatus for the production of block anodes, whereby block anodes of high density, that is to say, of better quality, can be produced simultaneously in large numbers per unit of time.

In using the apparatus of the invention, this is attained, by evacuating the material to be pressed immediately before the actual pressing operation. The pressed material can then advantageously be compressed in as short a time as may be desired. Harmful air bubbles occasioning porosity are no longer to be feared, since the pressed material introduced into the container is free from air.

Furthermore provision is made for bringing the pressed material into the container of the press under atmospheric pressure, shutting off in an airtight manner the press chamber enclosed in the container, and then evacuating the press chamber, and letting the press rams slide through the packings into the avacuated container. In this way the volume to be evacuated is kept extremely small.

In a further development of the invention, for the carrying out of the process, packing rings slidably mounted upon the press rams and sealing the container in an airtight manner are provided, and these packing rings are constructed as suction nozzles or connections for evacuating the container. The packing rings are constructed with at least one inner packing ring slidably mounted upon the press ram, and an outer packing ring secured upon the adjacent end face of the container or bearing upon it during the evacuation, the packing rings compensate, by an articulated arrangement of the inner packing ring to the outer packing ring, for any deviation of the press-ram axis from a position perpendicular to the plane in which the adjacent end face of the container lies, and the packing rings, during the evacuation and pressing, accommodate the pressed material issuing from the container, in such a way that the latter does not contaminate the packing sleeves of the inner and outer packing rings and diminish their sealing effect.

Furthermore there is provided in the packing rings a filtering or screening ring filtering the air drawn in by suction, the diameter of this ring being equal to the diameter of the bore of the container. Hence the suction pipes leading to the suction nozzles or connections of the packing rings are advantageously not contaminated, and the filtering or screening ring is cleaned at each pressing operation by the press ram, in that the press ram, with its end face, pushes the press material adhering to the filtering or screening ring into the container.

One embodiment of apparatus for carrying out the process is illustrated by way of example in the accompanying drawings, in which:

FIG. 1 shows a press, in the container of which the press material is evacuated immediately before the pressing operation; and

FIG. 2 shows the container of the press of FIG. 1 on a larger scale.

Press rams 2 and 3 of a press A are movable in a vertical direction in a container 1. Upon the press ram 2 a packing ring 4, with an inner packing ring 4a, is slidably mounted. The packing ring 4 bears, under its own weight, on a collar 2a of the press ram 2, or is pressed against the collar 2a with spring force, and bears with an outer packing ring 41; upon the adjacent end face of the container 1, when the press ram 2 moves into the container 1. The inner packing ring 4a forms, with the outer packing ring 4b, a ball-and-socket joint, with which the outer packing ring 4b still bears correctly for sealing upon the adjacent end face of the container 1 even if the axis of the press ram 2 is not exactly perpendicular to the plane of the adjacent end face of the container 1.

Upon the press ram 3 a packing ring 5, with an inner packing ring 5a, is slidably mounted. The packing ring 5 is secured with an outer packing ring 5b to the adjacent end face of the container 1, and the inner packing ring 5a, by power means arranged between the inner packing ring 5a and the outer packing ring 5b, in this case by hydraulic cylinders 50, is movable along the press ram 3 independently of the outer packing ring 522.

When required, the press ram 3 is moved out of the container 1 so far that only its collar 3a is still just within the container 1, and the press ram 2, with the packing ring 4, is raised so far that press material, in this case anode material, can be poured into the container 1, from a filling hopper or funnel C, which is movable for this purpose in guides B into a position above the container 1. After this charging operation, the end face of the container 1, upon which the outer packing ring 4b is to bear, is cleaned by a stripper D located on the under side of the filling funnel C, and the press ram 2, which previously, as represented in dot-and-dash lines in FIG. 1, had been shifted sideways in order to make room for the filling funnel C, is moved back into the axis of the press, and, with the packing ring 4, is lowered so far that the outer packing ring bears upon the adjacent end face of the container 1. By the power means c the inner packing ring 511 is now drawn towards and against the outer packing ring 512, and, through the packing rings 4 and 5, the air located in the container 1 and in the anode material, is sucked away.

For this purpose, in the outer packing ring 5b, at least one bore is provided with a coupling piece for a suction pipe leading to a vacuum pump, and the inner packing ring 4a is provided with bores 40. The bore 4c is continued as part of the suction pipe leading to the vacuum pump in bores 2b in the press ram 2.

After a suitable fall of pressure has been adjusted in the container 1, the anode material is compressed by the press rams 2 and 3, whilst the partial vacuum in the container is still maintained. Under these circumstances, during the operation, some anode material falls between the container wall and the press rams 2 and 3 into the packing rings 4 and 5. Whilst the anode material drawn upwards by suction after the lifting of the packing ring 4 remains lying upon the end face of the container 1 or is swept away, the anode material that has fallen or been sucked downwards accumulates, during the evacuation and pressing in the packing ring 5, which therefore forms, with its outer packing ring 5b and inner packing ring 5a, a chamber or space of a volume corresponding to the volume of anode material to be accumulated, and its inner packing ring 5a is therefore moved away from the outer packing ring 5b for the purpose of emptying this space.

During the emptying of the packing ring 5, the outer packing ring 5b and the inner packing ring 5a together form a sort of funnel directing the material passing through it away from the axis of the press ram 3. After the pressing the press ram 2 is lifted so far, or the container 1 is lowered so far, that the finished block anode can be pushed out of the container 1 by the press ram 3, and can then be pushed by a stripper E on to a delivery roller table F for removal. After this stripping of the finished block anode, the container 1 is moved back into its initial position to be refilled with anode material.

With horizontal presses, according to the method of this invention, instead of the packing rings 4 and 5, two packing rings are provided with inner and outer packing rings similar in their operation to the inner packing ring 511 and the outer packing ring 5b, the funnel-like arrangement for emptying the accumulated anode material being formed particularly by the diffusor-like widening of the outer packing ring 5b.

Provision is furthermore made for the employment of packing rings which already seal the container '1 even when the end face of the press ram is spaced away from the container by the height of a filtering or screening ring, and its inner packing ring is continued in the filtering or screening ring, and its outer packing ring is constructed as a suction nozzle or connection. The filtering or screening ring has a diameter equal to that of the bore of the container 1, or very slightly larger than the diameter of the press ram, and, firstly, prevents the suction pipes to the vacuum pump being contaminated, in that the air sucked in is filtered, and, secondly, the filtering or screening ring, at every pressing operation, is cleaned by the press ram, in that the press ram, with its end face, pushes the anode material adhering to the filtering or screening ring into the container.

We claim;

1. Apparatus for briquetting pulverulent and granulated materials, particularly anode material for the production of aluminium, comprising a press, having at least one press ram, a container enclosing at least one press chamber, means for evacuating the container, and packing rings slidable upon the press ram for closing the press chamber in an airtight manner, the packing rings being constructed as suction connections for evacuating the container.

2. Apparatus for briquetting pulverulent and granulated materials as claimed in claim 1, further comprising: at least one inner packing ring slidably mounted upon a press ram and an outer packing ring bearing during the evacuation upon the adjacent end face of the container, the said inner packing ring pivotally engaging the said outer packing ring.

3. Apparatus for briquetting pulverulent and granulated materials as claimed in claim 2, the said inner packing ring forming a ball-and-socket joint with its associated outer packing ring.

4. Apparatus for briquetting pulverulent and granulated materials as claimed in claim 1, further comprising at least one inner packing ring slidably mounted upon a press ram, and an outer packing ring secured to the adjacent end face of the container, the said inner packing ring being movable upon the press ram independently of the outer packing ring.

5. Apparatus for briquetting pulverulent and granulated materials as claimed in claim 4, the said outer packing ring, when the said inner packing ring is bearing upon it, constituting a chamber for accommodating pressed material escaping from the container during the evacuation and pressing, whereas the said outer packing ring, when the said inner packing ring is moved away from it, acts like a funnel.

6. Apparatus for briquetting pulverulent and granulater materials as claimed in claim 1, further comprising a filtering and screening ring located in at least one of the packing rings, the diameter of this filtering and screening ring being equal to the diameter of the bore of the container.

7. Apparatus for briquetting pulverulent and granulated materials as claimed in claim 1, comprising: at least one press ram formed with a bore, and at least one packing ring formed with a bore, these bores forming part of the communication between the interior of the container and the evacuating means.

References Cited UNITED STATES PATENTS 2,869,174 1/1959 Van Hardesveldt. 3,156,011 11/1964 Olson 1816M 3,245,119 4/1966 Huddleston 18l6M 3,328,838 7/1967 Zeitlin 18--16M 3,379,043 4/1968 Fuchs 18-16MX I. HOWARD FLINT, JR., Primary Examiner US. 01. X.R. 1816; 264-91 

